A Novel Mutation in VKORC1 and Its Effect on Enzymatic Activity in Japanese Warfarin-Resistant Rats
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- TANAKA Kazuyuki D.
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita-18 Nishi-9, Kita-ku, Sapporo, Hokkaido 060–0818, Japan
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- KAWAI Yusuke K.
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita-18 Nishi-9, Kita-ku, Sapporo, Hokkaido 060–0818, Japan
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- IKENAKA Yoshinori
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita-18 Nishi-9, Kita-ku, Sapporo, Hokkaido 060–0818, Japan
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- HARUNARI Tsunehito
- Technical Research Laboratory, Ikari Corporation, Chiba 260–0844, Japan
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- TANIKAWA Tsutomu
- Technical Research Laboratory, Ikari Corporation, Chiba 260–0844, Japan
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- FUJITA Shoichi
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita-18 Nishi-9, Kita-ku, Sapporo, Hokkaido 060–0818, Japan
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- ISHIZUKA Mayumi
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita-18 Nishi-9, Kita-ku, Sapporo, Hokkaido 060–0818, Japan
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抄録
Warfarin is a rodenticide commonly used worldwide. It inhibits coagulation of blood by inhibiting vitamin K 2,3-epoxide reductase (VKOR) activity. An inadequate supply of vitamin K blocks the production of prothrombin and causes hemorrhage. Recently, warfarin-resistant brown rats (Rattus norvegicus) were found around the Aomori area of Japan. There is no significant difference in the metabolic activity of warfarin in sensitive and resistant brown rats. To clarify the mechanism underlying warfarin resistance, we cloned the VKORC1 gene from rats and identified a novel substitution of arginine to proline at position 33 of the VKORC1 amino acid sequence. Then, we determined the differences in kinetics of VKOR activity between warfarin-resistant and sensitive rats. Hepatic microsomal VKOR-dependent activity was measured over a range of vitamin K epoxide concentrations from 6.25 to 150 μM. The Vmax values of resistant rats (0.0029 ± 0.020 nmol/min/mg) were about one tenth of those of sensitive rats (0.29 ± 0.12 nmol/min/mg). The Km values of resistant rats (47 ± 32 μM) were similar to those of sensitive rats (59 ± 18 μM). Warfarin-sensitive rats exhibited enzyme efficiencies (Vmax/Km) which were ten-fold greater than those observed in resistant rats. It may mean that VKOR activity of warfarin-resistant Aomori rats is almost lost, because their enzymatic efficiencies are very low even without warfarin. Further studies are needed to clarify how these rats can survive with a markedly reduced VKOR activity and how they simultaneously exhibit warfarin resistance.
収録刊行物
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- The Journal of Veterinary Medical Science
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The Journal of Veterinary Medical Science 75 (2), 135-139, 2013
公益社団法人 日本獣医学会
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詳細情報 詳細情報について
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- CRID
- 1390001206430441344
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- NII論文ID
- 130001879668
- 40019597159
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- NII書誌ID
- AA10796138
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- COI
- 1:STN:280:DC%2BC3s%2Fgslymug%3D%3D
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- ISSN
- 13477439
- 09167250
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- NDL書誌ID
- 024302751
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- PubMed
- 23018795
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- NDL
- Crossref
- PubMed
- CiNii Articles
- KAKEN
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- 使用不可